Sulfonate manufacture



May 22, 1956 u. B. BRAY ,SULFONATE MANUFACTUR 2 Sheets-Sheet l Filed Sept. l5, 1952 May 22, 1956 u. B. BRAY SULFONATE MANUFACTURE 2 Sheets-Sheet 2 Filed Sept. l5, 1952 WlFWig OF NOTI( HHIWIH mg mms3@ w23 mmf( Kunz mQZOU @nf BR Y Aff

sULroNATE MANUFACTURE Ulric B. Bray, Pasadena, Calif., assignor, by mesne assignments, to Bray Oil Company, Los Angeles, Caiif., a limited partnership Application September 15, 1952, Serial No. 309,730 9 Claims. (Cl. 1760-504) This invention relates to a process of manufacturing sulfonic acids and sulfonates from hydrocarbons, particularly petroleum hydrocarbons. The invention also relates to the manufacture of oil soluble sulfonates of the alkaline earth metals, particularly calcium, barium and strontium. More particularly the invention relates to oil soluble sulfonates free from chlorides and suitable for use in compounded lubricants.

The invention is illustrated by drawings showing in Figure l, apparatus for carrying out one modification of the process wherein a solvent alcohol is employed which is preferentially oil soluble having four to six carbon atoms in the molecule. Figure 2 shows an apparatus suitable for another modification wherein a preferentially water soluble alcohol is the solvent.

One object of the invention is to provide a process for making two or more sulfonates of different metals or ammonium from a given sulfonation mixture. Another object of the invention is to make calcium, barium or other sulfonate free of chloride ion. Still another object of the invention is to eliminate the use of costly alkali for neutralizing contaminating acid and sludge in the manufacture of sulfonic compounds.

It has heretofore been the practice to make sulfonates by treating a petroleum hydrocarbon fraction with furning sulfuric acid, separating the sludge and unused acid and recovering the sulfonic compounds from the sludge and from the unsulfonated hydrocarbon. Preferentially water soluble or so-called green acids were found in the sludge while the preferentially oil soluble or mahogany acids were found in solution in the oil along with some contaminating green acids and sulfuric acid emulsilied therein.

In most of the prior art, the sulfonates were merely a by-product from the manufacture of industrial and medicinal White oils. Recovery of the mahogany sulfonates has commonly been effected by washing the acid treated oil with caustic soda, then extracting the sulfonates with a solvent such as a mixture of water and a lower boiling alcohol, e. g., methanol, ethanol or isopropanol.

When desired, the soda mahogany sulfonate thus obtained has been converted into calcium, barium or other metal sulfonate by treatment with the appropriate salt, usually after purification to remove inorganic salts and green acid sulfonates. Thus, treatment with excess calcium chloride yields the calcium sulfonate and sodium chloride which is discarded with the excess calcium chloride. Attempts to avoid the waste of sodium hydroxide in this two stage neutralization and conversion, by direct neutralization of the sulfonic acid with lime have not been successful because of the formation of troublesome calcium sulfate slime and because of the diliiculty of separating contaminating green acid sulfonates from the mahogany sulfonates when in the form of their calcium soaps.

I have now discovered that calcium, barium and other metal sulfonates can be made readily and in high state of purity by first neutralizing the sulfonic acid with ammonia. The ammonium soaps are easily purified, then 'nited States arent e 2,746,987 Patented May 22, 1956 converted into the desired metal sulfonate by reacting them with the appropriate metal hydroxide or oxide. The proc` ess will be easily understood by referring to the drawing. In Figure 1, a hydrocarbon oil is introduced by line 10 into mixer 11 where it is intimately mixed with fuming sulfuric acid introduced by line 12 at the rate of about l to 2.5 lbs. per gallon of oil. The oil employed may be a distilled lubricating fraction of crude petroleum, preferably a naphthenic crude, although various special hydrocarbon fractions can be used such as a sulfur dioxide extract or other solvent extract having a high content of aromatics. I may also employ an aromatic alkylate in which an aromatic nucleus such as benzene, xylene, naphthalene, etc. is alkylated with long chain olelines such as polyisobutylene, polypropylene, cracked paraflin wax, etc. In general, I employ hydrocarbons boiling above about 600 F. as the charge to the sulfonation reaction. These stocks usually have a Saybolt Universal viscosity at F. in the range of about 100-600 sec.

It is desirable that the oil employed be partially refined before sulfonation to eliminate readily carbonized constituents of an unsaturated nature. For this purpose, treatment with 93 to 98% H2SO4 is satisfactory. Aluminum chloride, fullers earth and/ or other reagent effecting polymerization of oletnes can be employed also. Controlled solvent extraction with furfural, phenol, etc. can be employed to remove a large portion of the sludge forming constituents without removing excessive amounts of the desirable sulfonatable constituents.

Acid employed for sulfonation can be sulfuric acid above about 98% H2804 concentration. Fuming acid of 104% to 120% is usually employed. It is important to control the temperature of the reaction not to exceed about F., in order to avoid destruction of the desired sulfonates. It is also important to restrict the time of contact between the acid and the oil forthe same reason. Excellent results can be obtained by mixing and cooling in stages. Thus the reaction mixture from mixer 11 passes through cooling coil 13, then to mixer 14, where it is mixed with more acid charged by line 15. Thorough mixing is facilitated by recycling the mix with pump 16.

The additional acid added through line 15 may have a higher concentration than the acid added by line 12. Thus the initial acid may have a strength of 104% while the acid charged at 15 can be 120%. Likewise, the amount of acid charged at the later stages can be increased. Any convenient number of acid injection stages can be employed but usually two or three stages are suliicient. Sludge may also be withdrawn between treating stages if desired.

From mixer 17, the oil and acid are recycled through cooler 18 by pump 19, thence flowing to cooler 20 and through line 21 to settler 22. It is usually desirable to add a small amount of water by line 23 to reduce the strength of the acid and terminate the sulfonation reaction. About l to 3% of water based on the oil charged is sufiicient. Water also aids in the separation of sludge in settler 22. Heat produced in dilution of the acid is removed by cooler 20.

Separation of sludge from oil in 22 is facilitated by adding a hydrocarbon solvent by line 24 and for this purpose, about 1/4 volume to l1/2 volumes per volume of acid oil is effective. Petroleum naphtha boiling in the range of about to 350 F. is suitable but I prefer to use aromatic hydrocarbon solvents such as benzene, toluene, xylene or cracked or reformed naphthas high in aromatic components. The aromatic hydrocarbon solvents have the advantage of extracting a higher proportion of the desired oil soluble sulfonic acids from the sludge layer. Besides giving an increase in the yield, the solvent also produces a lighter color in the final product.

Inwsettler 22, la ,sludge layer cpmprising the green acids, sulfuric acid and some entrained oil is withdrawn by line and discarded from the system. If desired, the sludge may be processed to recover sulfuric acid and the green acids by means well known inr the art. Also the sludge may be re-extracted with fresh hydrocarbon solvent which extract maybe used to extract the primary reaction mixture inline 21, thus furnishing a countercurrent use of the solvent.

The upper layer in settler 22` comprising unreacted oil and oil soluble sulonic acids together with solvent if one is used, is drawn o by line 26 to lmixer 27 wherein it is neutralized with ammonium hydroxideintroduced by line 28. YIt is desirable to employ an ammonia solution of about l() to 30 percent by Weight in an amount suicient to completely neutralize the acid in the oil stream with some excess. Mixer 27 and line 26 can be resistant to dilute acid, for example lead or stainless steel may be employed in their construction.

Frommixer 27 the oil flows to solvent stripper 29 where the hydrocarbon solvent is stripped oi with steam o rheat from coil 3l). Solvent vapors, NH3 and steam pass by line 3l to condenser 32 and thence to absorber 33 wherein the ammonia is absorbed from the solvent by a water stream entering by line 34 and leaving by line 35. The solvent stream liows thence by line 36 to solvent storage 37. If desired, an aqueous layer or ammonium sulfate brine can be separated from the stream leaving mixer 27 before stripping by means not shown.

From the stripper 29 the sulfonate-oil stream passes by line 38 to mixer 39 then into settler 40. Partitioning solvent is added to the oil stream in mixer 39, entering by line 41. For this purpose l prefer to use a butyl alcohol, for example secondary butyl alcohol, although I may also use amyl and hexyl alcohol. Alcehols and amines of four to six carbon atoms are generally suitable, the preferred solvent being preferentialiy soluble in oil but also appreciably soluble in water. Triethyl amine and mixtures thereof and mixtures with alcohols can be used. The preferred amount of partitioning solvent is about 10 to 40 'parts per 100 partsY of oil and sulfonate with water in proportions of about 2O to 60 parts per 100 parts of oil and sulfonate. In some cases we may wish to increase the ratio of solvent to sulfonate and oil to equal parts or more maintaining a sufficient ratio of water to sull fonate to give an aqueous brine phase upon settling, containing ammonium sulfate. With higher ratios of alcohol and decreasing ratios of water WithV respect to oil and sulfonate, crystals of ammonium sulfate are precipitated along with decreasing amounts of brine. Y added, and the ratio of alcohol is high, all the (NH4)2'SO4 can be separated as a solid by centrifuglng, settling or filtering the mixture of alcohol, oil and sulfonate. After removal of (NH4)2SO4, either as a concentrated brine or crystals, the salt-free solution can then be treated with Water in the proportions given above to elect separation of lubricating oil from the mixture.

The mixture of oil, solvent and Water is held in settler 40 for suicient time to effect a separation into two or three layers, depending on conditions. The separation is facilitated by holding the temperature at about 140 to 180 F., and maintaining the hydrogen ion concentration at about pH 6 to 9 which is readily done by removing excess NH3 in stripper 29. The bottom layer in settler 4t) comprising ammonium sulfate, Water and a small amount of green acid sulfonate is drawn off byline 42 to heater 43 and stripper 44. A basic metal hydroxide such as lime slurry is introduced by line 4S in an amount sufficient to liberate all the NH3 and other basic nitrogen compound which may be present. Heat supplied by coil 46 in tripper 44 drives oft the NH3 through line 47 leading to condenser 48, thence to separator 49 wherein the solvent separates from the Water and ammonia and is ready for re-use in the system. The lime slop from the base of stripper 44 When no water is 4 comprised of Ca(OH)2 and CaSOi is discharged from the system by line 59.

in asimilar manner the ammonium sulfonate phase is withdrawn by line S1, heated in heater S2 with lime or other metal hydroxide or oxide base introduced by line 53. The sulfonate passes thence to separator 52a, Where the aqueous phase is separated and Withdrawn by line 52h, leading to stripper 44. The upper layer in 52a, comprised of metal sulfonate and solvent with dissolved ammonia, passes by line 54 to stripper 55 Where vapors of ammonia and Water are removed through line 56. When desired to produce a highly alkaline product, additional Ca(OH)2 siurry is introduced into line 54 by means not shown. Also-the mixture entering stripper 55 may be reheated to a higher temperature by suitable means not shown in order to facilitate both alkalizing and distillation operations conducted in stripper 55. The concentrated calcium sulfonate or other metal sultonate corresponding with metal hydroxide introduced by, line 53, is withdrawn through line 57 to Yfilter 53, thence to storage tank S9. Diatomaceous earth filter aid can be introduced by line 6), if desired, to give a bright product and remove cloud.

The upper layer in settler 40 is a clear oil with a trace of sulfonate containing lsome partitioning solvent. It is drawn to stripper 61 where NH3, alcohol and water are taken overhead through vapor lines 62 and 47. Lime introduced at 63 converts the trace of ammonium sulfonate to calcium sulfonate in heater 64. Oil from 61 passes by line 65 to filter 6 6 and storage tank 67, filter aid being introduced at 68. If desired, the by-product oil in 67 can be blended with the sulfonate in 59 by line 69 leading to tank 7i) to provide a product of the desired sulfonate content.

Make-up ammonia can be supplied to the system in the form of anhydrous orA aqueous ammonia. Use of anhydrous ammonia has the advantage of balancing the water in the system more easily. When employing hydrocarbon solvent to aid sludge separation in settler Z2, it is desirable to avoid introducing partitioning solvent into neutralizing mixer 27. By maintaining a high concentration of NHrOH in supply tank 49, the solubility of the partitioning solvent therein is reduced to a negligible amount. When no hydrocarbon solvent is employed in the system, the stripper 29 is bypassed by a line not shown passing from mixer 27 directly to settler 40, and the partitioning solvent stream is introduced with the ammonia into mixer 27.

When employing an amine as the partitioning solvent such as di ethyl or di propyl amine, I can dispense with the use of ammonia by supplying sufficient solvent to effeet the neutralization of vthe sulfonic acids, sulfuric acid and otherV acids remaining in the oil after separation o sludge. The use of hydrocarbon solvent should be avoided when operating in this manner'because of contamination of one solvent with the other and possible loss of amine solvent in the acid sludge withdrawn at 25, unless thetwo solvents' are separated during recovery by eicient fractionation.

Another modication of my process involves the use of preferentially Water soluble partitioning solvents as exemplilied by methyl, ethyl and isopropyl alcohol, in combination with an aromatic hydrocarbon solvent such as benzene, toluene or xylene. The Water soluble solvent is referred to herein as a polar solvent, and includes certain of the water soluble amines. A plant operating in this way is shown in dow diagram in Figure 2. Oleum from line v and sulfonatable hydrocarbon oil from line 81 are mixed in mixer 82j, cooled in coil 83, recycled and mixed further in centrifugal pump 84, andmixed in S5 with a second portion of acid from line 86, cooled in coilV 87 and recycled'by pump 88. The temperature of the sulfonation is held below about F. to avoid overtreating. A small amount of water is next added by line 89 and the heat of dilution is absorbed'by mixer 90. rlihe water reduces the acid concentration to a point Where sulfonation is largely checked. An aromatic solvent is thenin'troduced by line 91 to dilute the oil by about-M4- to 1%/2 volume of solvent per volume of oil treated. It is important to dilute the acid with sucient water to prevent sulfonation of the aromatic solvent and consequent formation of low molecular weight sulfonic acids. Excessive water must be avoided, however, owing to the release of undesirable color bodies from the sludge by the action of water.

The acid oil and solvent passes by line 9'2 to settler 93 where the sludge drops out and is Withdrawn by line 94. Instead of operating in a continuous manner as shown, l may settle the sludge batchwise in a tank. The oil layer containing the desired mahogany acids which are preferentially oil soluble, is withdrawn by line 95 to neutralizing mixer 9e where it is rapidly neutralized with aqueous ammonia and simultaneously mixed with polar solvent introduced by line 97. The amount of polar solvent required is preferably about equal to the volume of aromatic solvent present but the ratio can be varied, for example from about 1:3 to about 3:1. The amount of water employed is usually about equal to the volume of polar solvent, varying from about lz2 to about 2:1. Excess NHtOH can be employed if desired to assure neutrality.

From mixer 95 the oil and solvent mixture passes by line 98 to settler 99 where there are formed two or three distinct phases, depending on the ratio of solvent to water and oil. On the bottom is a brine layer consisting mainly of water and (Nl-lQaSOi with some undesired ammonium salts of preferentially water soluble sulfonic acids.

'This phase is withdrawn by line lll@ leading to heater 3.01 and stripper M2. A strong inorganic base is introduced by line 21% to liberate the ammonia from the brine. ln stripper the NH3 and solvent vapors are led by line lil-tl to condenser 165, thence to separator and storage reservoir ldd wherein the hydrocarbon solvent forms an upper layer with the ammonia solution of the polar solvent on the bottom. From the bottom of stripper 102, the sludge of calcium sulfate and excess calcium hydroxide free of ammonium salts and solvent is discarded by line M7. The ammonium sult'onate phase is withdrawn from settler 99 by line M33 leading through heater 109 and thence to separator @9a. A metal oxide or hydroxide, for example lime, is introduced by line 111 to convert the ammonium sullonate to metal sulfonate. An aqueous phase separating in 169@ is withdrawn by line 199e leading to stripper lllZ for recovery of ammonia and solvent contained therein. The metal sulfonate layer is conducted by line 29% to stripper llt? where the liberated ammonia, water and solvent vapors are expelled r through line 112. Ammonia and solvent vapors, mostly polar solvent. are conducted by line Ilild through condenser lilS to storage reservoir lt. Ammonia, polar solvent and water collect in the bottom of reservoir litio while. the hydrocarbon solvent forms an upper layer therein. Solvent-free sulfonate in oil with some excess lime passes by line il to tilter L14 and thence to storage tank llS. Filter cel can be introduced by line H6 to brighten the product when needed.

When it is desired to manufacture ammonium Isulfonate without conversion to metal sulfonate, the introduction or" lime or other metal base by line lll is omitted. When operating in this manner, stripper lill serves to eliminate solvent and water from the sulfonate, producing a clear solution of ammonium sulfonate and hydrocarbon oil, e. g. 25d-0%, which can be iiltered in 11d in the same manner the metal sulfonate when desired. To prevent development ot acidity in the ammonium sultonate by hydrolysis, NH3 gas can be introduced in a slow stream into the base of stripper tower lll). Ammonium sul- Vronate prepared in this manner can be stored as an intermediate product and later converted to any desired metal sultonate by mixing with a suitable metallic base and heating to expel ammonia vapors.

Before the hydrocarbon solvent in tank 105 can be recycled to the acid oil in line 92, it triust'be'freed of NH'a and polar solvent. This is accomplished by scrubbing with water in scrubber 127, the solvent entering the scrub ber by line 128 and leaving by line 91. Extracted NH3 and polar solvent in water passes by line 130 to storage tank 106, Water being supplied to the scrubber by line 131. Makeup hydrocarbon solvent is supplied by line 132 while polar solvent is supplied from tank 133 to make up losses. Makeup ammonia is supplied by tank 134.

ln describing the invention particularly with reference to the drawings l have described the use of lime to convert the ammonium sulfonate to calcium sulfonate, but it should be understood that other bases such as the hydroxides of sodium, lithium, potassium, strontium and barium, may be employed to produce the corresponding sultonate. ln fact, I may employ any base, oxide or hydroxide which is capable of displacing ammonia from the ammonium sulfonate solution in polar solvent. Distillation of solvent from the mixture accelerates the conversion by shifting the equilibrium with removal of NH3 with the solvent vapors. At the same time, the polar solvent in combination with water ionizes the basic metal compound. l may thus etlect conversion with metal oxides and hydroxides of very slight basicity such as zinc, aluminum, lead, cadmium, molybdenum, magnesium, copper, etc.

ln carrying out my process, it is not necessary to con* centrate the sult'onate for many purposes and I may adjust the conditions of solvent, water and temperature to separate only two phases in settlers 40 and 99, an oilsulfonate phase and an aqueous phase.

l have found that the conversion of ammonium sultonale in oil solution with excess metal base yields a basic metal sulfonate which has a high alkali value because of the presence of metal oxide or hydroxide above the stoichiometric amount. Where the metal sulfonates are used to control corrosion, and also as engine oil additives, the excess metal is an important advantage. For some purposes l may prepare the ammonium sulfonate without conversion to metal sulfonate. Thus l may employ ammonium sulfonate in anti-rust oils in which case I prefer to add a slight excess of NH3 to render the sulfonate basic, by an amount of l0 to 50 mg. KOH per gram equivalent, for example.

ln describing the separation of sludge from sulfonated oil, l have specified the use of aromatic hydrocarbon solvents which reduce the viscosity of the oil and improve sludge separation. They also can increase the yield of sulfonate by extracting oil soluble sulfonic acid from the sludge phase. ln addition to aromatic hydrocarbon solvents, l can also use paratiinic type solvents `such as petroleum naphtha, particularly in that modification of my process shown in Figure l. Owing to the lower solvent power of the parairinic hydrocarbons for mahogany sulfonic acid, a larger proportion of paralinic solvent is required to obtain maximum yield of mahogany sulfonic acids.

Although I have described specific procedures for purifying the ammonium sulfonate produced in accordance with my process, it should be understood that my invention is not limited thereby but that any conventional procedure may be employed for extracting the ammonium sulfonate and separating ammonium sulfate therefrom prior to conversion to metal sulfonate. Thus I may employ anhydrous isopropyl alcohol, anhydrous methyl or ethyl alcohols alone or in combination with benzene or other hydrocarbon solvent for the separation of ammonium sulfate from the ammonium sulfonate phase. In general, however, extraction with butyl alcohol is preferred.

Having thus described my invention, what l claim is:

1. The method of making oil soluble sulfonates of metals which comprises sulfonating an aromatic type hydrocarbon lubricating oil, adding a hydrocarbon solvent, separating acid oil, containing dissolved oil soluble sulfonic acids and solvent from excess acid and sludge, neu- 7 tralizing said acid oil and solvent solution, with ammonia, -thereby converting the said sulfonic acids to ammonium =sulfonates, heating said oil and su'lionates with a basic metal compound, thereby expelling vapors olf ammonia vand solvent and forming the metal sultonate and recovering the oil and dissolved metal sulfonate.

l2. The method vof claim 1 wherein said basic metal compound is calcium hydroxide.

3. The method of claim 1 wherein said basic metal compound is .sodium hydroxide.

4. The method of claim 1 wherein said basic metal compound is barium hydroxide.

5. The method of claim l, wherein said ammonium sulfonates are purified to remove ammonium sulfate before heating with said basic metal compound.

6. The method of making oil soluble sulionates of metals which comprises Vsulfonating a hydrocarbon having a boiling point above about y600" F., separating the sulfonated-oil from excess acid and sludge, in the presence of a solvent for said oil, neutralizing the sulonated oil with antimonia and removing lsolvent and excess ammonia from said oil, preparing a mixture of the oil with water and a polar solvent Vof the class consisting or" alcohols and amines having not more than six carbon atoms which is substantially soluble in water and also in oil, allowing the mixture to separate into three phases, an aqueous phase, a -sulfonate phase and an oil phase, separating the sulfonate phase, heating it with a basic metal-oxygen compound, thereby liberating ammonia vapor and converting the sulfonate to a metal sulfonate and recovering said metal sulfonate.

7. The method of claim 6 wherein said polar solvent is an alcohol.

8. The method of claim 6 wherein said polar solvent is an amine.

9. The method of making sulfonates of metals which comprises sulfonating an aromatic :lubricating :oil vwith tunning sulfuricacid under Vcontrolled temperature conditions :to give. anoilcontaining about .ten tothirty percent oisulfonicacid, adding suicient water vto substantially prevent furtherl sulfonation, .adding an. aromatic hydrocarbon solvent toassist vseparation .of sludge, removing the `snlfonated -o'il phase and solvent from excess acid and sludge, neutralizing the sulfonated oil with ammonia and Water, adding a polar solvent selected from the class consisting of alcohols and amines `having not more than six carbon atoms miseible with water in all proportions which is also a solvent for oil, separating the oil, Water and solvent into at least two phases, an aqueous phase containingammonium salts and a sulfonate phase, separating the snlfonate phase and heating it with a basic metal compound while withdrawing vapors of solvent and ammonia, recovering the solvent and ammonia for reuse in the system and recovering the metal sulfonate.

References Cited in the file of this patent UNITED STATES PATENTS 1,524,859 Forrest et al. Feb. 3, 1925 2,121,845 Wernicke Iune 28, 1938 2,187,883 Lemmon Jan. 23, 1940 2,307,953 Potter Ian. 12, 1943 2,397,191 Meyer Mar. 26. 1946 2,406,763 Gresinger Sept. 3, 1946 2,451,549 Gzemski Oct. 19, 1948 2,453,690 Bray Nov.. 16, 1948 2,487,080 Swenson Nov. 8, 1949 2,509,863 Harlan May 30, 1950 2,543,885 Wilson Mar. 6, 1951 2,559,439 .Tones et al. July 3, 1951 2,578,657 Anderson et al. Dec. 18, 1951 2,650,198 Kronig et al. Aug. 25, 1953 

1. THE METHOD OF MAKING OIL SOLUBLE SULFONATES OF METALS WHICH COMPRISES SULFONATING AN AROMATIC TYPE HYDROCARBON LUBRICATING OIL, ADDING A HYDROCARBON SOLVENT, SEPARATING ACID OIL, CONTAINING DISSOLVED OIL SOLUBLE SULFONIC ACIDS AND SOLVENT FROM EXCESS ACID AND SLUDGE, NEUTRALIZING SAID ACID OIL AND SOLVENT SOLUTION, WITH AMMONIA, THEREBY CONVERTING THE SAID SULFONIC ACIDS TO AMMONIUM SULFONATES, HEATING SAID OIL AND SULFONATES WITH A BASIC METAL COMPOUND, THEREBY EXPELLING VAPORS OF AMMONIA AND SOLVENT AND FORMING THE METAL SULFONATE AND RECOVERING THE OIL AND DISSOLVED METAL SULFONATE. 